The overall objective is to study the role of monoclonal cell populations in the origin and growth of atherosclerotic lesions. The isoenzymes of glucose-6-phosphate dehydrogenase will be used as cellular markers in black females heterozygous for the two isoenzymes to determine clonal characteristics. Animal models will also be used to study the same problem. A comparison of histologic, biochemical and clonal characteristics will be made in fatty streaks, gelatinous plaques and fibrous-capped plaques. Histochemical methods will be developed and then used to study scar formation and the development of arterial lesions. Clonal characteristics of thrombi in aneurysms and scars developing in skin will be studied.